Environmental Engineering Reference
In-Depth Information
b Examples: cadmium and arsenic.
7.2 BPA {2,2-BIS(4-HYDROXYPHENYL)PROPANE}
Over 65% of the global production of BPA is used to make PC and another
30% for epoxy resin production (Plastics Europe, 2010). Based on the 2010
data, however, only 7% of the PC was used in packaging and medical device
applications. Most are instead used in construction as glazing or in media
(CD and DVD applications) and in electrical/electronic applications. These
non-packagingusesposealowerrisk.Aboutathirdofthisglobalproduction
is used in the United States. BPA is perhaps the most controversial of
plastic-related EDCs present in the environment and is attributed to at least
the following sources (Geens et al., 2011).
1. Polycarbonate products
BPA PC resin is used to make baby bottles, water bottles, and food
storage containers (Mercea, 2009). Residual monomer BPA in the resin
is believed to leach out from the plastic package or containers into food
contents. The PC baby bottles, for instance, contain 4-141 ppm (median
10.5 ppm) of residual BPA (Leo et al., 2006). In addition, hydrolysis
(Aschberger et al., 2010) of PC at high temperatures may also generate
BPA monomer from the plastic material.
2. The epoxy resin lining of food and beverage cans
Metal cans that contain food or beverages employ a thin film of an
epoxy polymer on its inside surface to control corrosion of the metal
and to limit food contact with metal. Epoxy is ideally suited for this
application, and the type of epoxy used is predominantly (over 98%)
BPA-based. Both aluminum and steel beverage cans are typically
sprayed with a water-based epoxy-acrylic system, often with an amino
resin (or phenolic resin) to cross-link the lining (Oldring and Nehring,
2007).
The epoxy is made by reacting BPA with epichlorohydrin in the
presence of a base. As with PC, the BPA derived from the epoxy lining
can also leach into the consumable contents in the can. With about 17%
of the US diet coming from caned food, this is a serious concern.
3. Dental fillings
 
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